Conventionally, a buckle is used when both end portions of a belt binding a baggage or the like are connected, or when an ID card or a cellular phone and a strap for suspending the ID card or the cellular phone from one's neck are connected. As such a buckle, for example, a buckle, described in the following Patent Document 1 is proposed.
The buckle is formed by a male member and a female member mutually engaging. In the female member, there is formed an operation portion for releasing an engagement with the male member. The operation portion is formed by a C-shaped slit formed on a surface of the female member, and also a groove portion having a concave strip in a cross-sectional view formed on a surface of the female member in the same manner. The groove portion is provided between both ends of the C-shaped slit to form a thin hinge portion. The operation portion moves up and down as a supporting point of the thin hinge portion. Also, in the operation portion, one portion protrudes more than the surface of the female member, so that one's fingers are easily placed so as to facilitate an operation.